1. Field of the Invention
The invention relates to a method for the waste disposal of a high, and/or medium, and/or low expansion foam employed in connection with fire extinction.
2. Description of the Background of the Invention Including Prior Art
An air-foam method is used in connection with fire-extinguishing foams, where water is transformed into a phase having a lower specific weight, in particular in relation to ignitable and flammable liquids. For this purpose, a foaming-agent is admixed to a water stream and the foamable solution is foamed in a foam generator by drawing in of air. Foamable materials, which are employed for the formation of foam, are designated as foaming-agents. These foaming-agents are in part based on synthetic materials and they comprise for certain application compositions also special fluorotensides, which exhibit, on the one hand, an improved extinguishing effect but which, on the other hand, represent difficulties in connection with waste disposal. High, medium, or low expansion foam can be generated from a predetermined mixture of water and a corresponding foaming agent. The kinds of foams are defined according to their foaming numbers, i.e. the ratio of the unfoamed mixture relative to the generated foam volume. A high expansion foam has an expansion ratio of the fire foam of from 4 to 20, a medium expansion foam of from 20 to 200, and a low expansion foam of over 200 up to 1000. It can be recognized from this that both medium as well as high expansion foam result in large volumina of foam.
Fire-extinguishing foam is employed not only in case of a fire. It is indispensable to generate an extinguishing foam for test purposes. Fixed high and medium foam foam systems have regulators approval after a successful project performance involving a foam-generation test. In addition, foam carpets have to be generated in a mobile application for training of fire-fighters. The taking down and removal, decomposition and disposal of large volumes of high or medium expansion foam is accompanied today by substantial difficulties based on environmental protection considerations. The foaming agents, required for the generation of the foam, can in fact be biologically degraded. Nevertheless, the direct discharge of the foaming-agents into the ground water or into canals or, respectively, into a water-clarifier and water-treatment plant, or into a sewage-treatment plant, results in a sudden change of the equilibrium present in such plant and can thus lead to a disturbance of the water biology and water chemistry present in such plant and in the ground water and waterways. For this purpose, statutory limiting values have been fixed in various jurisdictions, which define a maximum permissible feeding of such foams per time unit into a channel grid. These statutory limits can practically not be maintained during the waste disposal of test foams or in case of foams actually applied in case of a fire.
The large volumes of foam generated had to be precipitated in the past with large amounts of water. Another method comprises in allowing the foam to rest and remain such that it is allowed to disintegrate and decompose by itself. However, this method requires a substantial amount of time.